Plug and feather construction



PLUG AND FEATHER CONSTRUCTION William B. Horton, Concord, Mass.,assignor to H. E.

Fletcher 00., West Chelm'sford, of Massachusetts Application January 30,1956, Serial No. 562,060.

" 1 Claim. (Cl. 125-36) with splitting stone, such as blocks of graniteand the like.

This class of splitting tool is useful in granite quarries in splittingslabs of granite which may have alreadybeen separated from a quarry bedat considerable expense and which are required to be subdivided with aminimum of waste into desired sizes. The plug and feather tool C011?sists essentially of a wedge-shaped plug and a pair of tapering metalpieces commonly referred to as feathers and adapted to be contained in adrilled hole in the granite slab. The Wedge-shaped plugis locatedbetween the feathers and serves to drive the feathers apart with greatforce when struck with a hammer If the splitting forces thus producedare exerted through the feathers against those portions of the piece ofgranite immediately surrounding the top of the drilled hole, there willoccur breaking or chipping of stone, a condition re ferred to asspalling and there results an undesirable spoilage of stone. To avoidthis, a conventional practice is to counterborethe top of the drilledhole a suflicientdepth to prevent spalling. However, thisisobjectionable in that itadds materially to the cost' of process ing thegranite. A

It is an object of the invention to provide an improved splitting toolof the plug and feather type and to devise especially a featherconstruction which can be used without spalling taking place and which,nevertheless, eliminates the need for counterboring, regardless of thesize of the. drilled hole into which the plug and feather assembly isinserted. It is a further object of the invention to provide, a tool ofthe class described which ismore efficient and convenient to handle and,especially, to position in. a drilled piece of granite.-

These and other objectsand novelfeatures 'will be apparent from thefollowing detailed discussion of the invention.

To deal with the problems and objectives outlined, I

have conceived of the idea of constructing feather components in a plugand feather assembly having as a basic feature stone engaging surfacessolimited in extent that they may be employed in a drilled hole to exertsplitting forces in a selective manner and particularly at points suf--ficiently below the top of a drilled hole to avoid spalling.

I have found that the stone engaging surface of a feather component maybe limited in a suitable manner by. providing an elongated feather bodyhaving a relatively thick bottom portion and a relatively thin upperextention. I construct this elongated body in a special manner such thatthe relatively thin extension has a dimension measured in a direction atright angles to its longitudinal axes which is small relative to acorresponding dimension of the relatively thick bottom portion so as tointerrupt and limit the extent of the area of contact of the stoneengaging surface of the thick bottom portion when wedged in a drilledhole.

Mass, a corporation nited States Patent structure of Fig. 6. I

7 Ice This concept, I find, may be practically and effectively embodiedin several different forms and three preferred forms have beenillustrated in the accompanying drawings, in which 7 Fig. '1 is aperspective view of theimproved feather construction of the invention;

Fig. 2 is a view in cross-section showing a pair of feathers and a plugarranged in an operating position in a drilled hole in a piece ofgranite;

Fig. 3 is another perspective view showing a modified form ofjfeatherarrangement, including apair of feather elements associated together;

Fig. 4 shows a fragmentary detailed plan view of a drilled hole in agranite body having the feather pair shown in Fig. 3 located therein;

Fig. 5 is a fragmentary cross-sectional view showing the feather pair ofFigs. 3 and 4 combined with a plug member in an operating position;

Fig. 6 is a fragmentary perspective view of still another modificationof the invention; and

Fig. 7 is a fragmentary cross-sectional view vIn the structureillustrated in Figs. 1 and 2, I have shown one simple .form of featherconstruction in which an elongated feather body, generally noted by theletter F, is constructed with a relatively thick bottom portion 2 and arelatively thin upper section 4. The feather is preferably constructedalong one side with a relatively fiat plug engaging surface 6 and alongits oppositeside with a curved stone engaging surface 8. The extension 4is preferably constructed with a slightly bent-over shape,

' as shown, which allows the end of the extension to project outwardlyand serve as a handle or .tip for holding and positioning the feather ina drilled hole.

In accordance with the invention, I interrupt and limit the convex stoneengaging surface 8 by abruptly relieving the extension 4 to define arelatively sharp shoulder 5 and thus leave a relatively thin portion, asshown in Fig. 1. In Fig. 2, I have further illustrated a pair offeathers combined with a plug 9 to constitute a complete splitting toolwith the feather components being engaged ina drill hole 10 of a pieceof granite 11. In the position shown, the plug 9 holds the stoneengaging surfaces as 8 firmly againstthe sides of the drilled hole.

It will be observed that, in the position described, the

feather extensions and plug have a combined dimension measured in adirection at right angles to the longitudinal' axes of these memberswhich is small relative to a corresponding dimension measured throughthe relatively thick stone engaging surfaces. As a result, there will beaclearance as noted at points C and C between the feather extensions andthe hole sides regardless of the position of the splitting tool, and theefiect of this is to localize the area of contact of the. stone engagingsurfaces of the two feathers at the lower section of the hole.

Under such conditions, I have found that, if the plug 9 is struck asharp blow, desirable wedging forces are developed and applied'at adistance sufficiently below the surface S of the piece of granite 11 toavoid spalling or otherwise damaging portions of stone immediatelysurrounding the drilled hole.

It is pointed out that, in thus limiting the area of contact of wedgingforces to the lower part of a drilled hole by means of the relievedfeather feature, not only do I succeed ineliminating spalling but thereis also avoided the need for counterboring since the ordinary drilledhole is all that is required to receive the plug and feather arrangementof the invention.

' In Figs. 3, 4, and 5, I have illustrated a form of featherconstruction in which there is retained the same basic feature of arelatively thick stone engaging feather portion and a relatively narrowor thin extension portion. 1With Patented- June 3, 1958 t of the thisfeature is, however, provided an additional feature of joining togetherthe feathers to make a connected pair and the connecting means may alsobe utilized to hold the feathers in a properly supported position in adrilled hole.

In forming this connected feather pair of the invention, I employ aconnector element, preferably consisting of a steel wire generallyindicated by the arrow W. The wire member W is folded upon itself toform a feather retaining loop portion 12 and two right angularlyextending legs 13 and 14'. These legs 13 and 14 are solidly attached, asby welding or other suitable means, to a pair of special feathersections 15 and 16 along inner surfaces 15a and 16:: thereof.

The feather sections 15 and 16 are formed with relatively short taperingstone engaging surfaces which are adapted to perform the same functionas surfaces 8, already described in reference to feather F. It will beseen that the parts of the wire W which extend upwardly from the feathersections, as illustrated in Fig. 3, serve to locate the feathersection's well below the top of the drilled hole.

In Fig. 4, I have illustrated the connected feather pair arranged in adrilled hole 20 in a mineral body 22, and this figure illustrates moreclearly the location of the loop portion 12 resting on the upper surfaceof the body 22 in a position such that the feather sections 15 and 16are suspended in spaced-apart relation well down in the hole.

In Fig. 5, I have shown the connected feather pair positioned in anoperative position in the hole 20 in the. mineral body 22 with a wedgemember 24 having been inserted between the feather sections 15 and 16.This figure further illustrates the location of the feather,

sections well below the surfaces of the mineral body 22 and also showsthat the wire member W occurs in spaced relation to the hole to leaveclearances 26 and 28 so that no wedging pressure is exerted in theregion near the top of the hole.

In this connected feather pair, certain handling and positioningadvantages are realized which are not possible with either theconventional type of feather or a feather such as shown in Figs. 1 and2. The loop portion not only serves to locate the feather sections deepin the hole but also holds the sections inany desired spaced-apartrelation to take the plug or Wedge member 24 and, when the hammering andsplitting operation has been completed, the loop portion 12 serves as amore con venient meansv of withdrawing both of the feather sections atthe same time,

In Figs. 6 and 7 I have illustrated still another modification of plugand feather construction in which somewhat the same basic principle ofthe invention is employed. Fig. 6 is a fragmentary, perspective view ofcomponent parts of the modification arranged for place- L ment in thehole 30 in a fragmentary portion of a mineral body 31 which is to besplit. Fig. 7 is a cross-section taken approximately on the centralvertical axis of the plug 34 has all its taper formed on oneside,-matching the'taper of feather 32; the opposite side of the plug 34is constructed with a cylindrical surface matching the inside surface ofthe shell 33.

Pig. 7 shows the surface of feather 32 which bears against the stonestopping short. of the top of the hole 30, the upper portion 36 of thefeather being merely a useful handle for positioning it, thus embodyingthe principle of the invention. Similarly the outer surface of shell 33stops short of the upper surface of the stone. The shell 33 mayor maynot have a projecting handle, but I have found it to be unnecessary andso in a preferred form I leave it off, as shown in Figs. 6 and 7.

From the foregoing description, it will be apparent that I have provideda desirable and simplified form of plug and feather tool which willavoid spalling and eliminate the need for counterboring. More convenienthandling and more accurate placing of the splitting tool can also becarried out.

The idea of relieving a feather extension or using a connecting meansfor joining two feather sections may be embodied in various other formsin addition to those noted in keeping with the spirit of the inventionas defined by the appended claim.

Having thus described my invention, what I claim is:

A feather member for a stone splitting tool of the plug and feather typefor use in a round hole in the stone, said feather member comprising anelongated body having a flat surface adapted to be engaged by a wedgeand having an opposite curved bearing surface for engagement with acurved inner surface of the round hole, the elongated body having arecessed portion above the. curved bearing surface and extending frombelow to above the top of the hole and having a portion adapted toextend above the top of the stone and bent outwardly to provide meansfor manually rotatably adjusting the plug in the hole. i

References Cited in the file of this patent UNITED STATES PATENTS1,034,860 Ballou Aug. 6, 1912 1,797,748 Alexander Mar. 24, 19312,093,452 Joy Sept. 21, 1937 2,225,852 Acordi Dec. 24, 1940 2,290,824Johnson July 21, 1942

